Mark Babb

Oh well, while we're on the subject of swapping. I too have a spare Med case 4.1 diff for an E30. Usual thing, read the Regs that state must use 4.1 diff and then set off to the BMW dismantles and asked for a 320 4.1 diff. Yes sir which size? Errrr not sure what you mean, so ended up buying both small case and med case 4.1 diff. So Med case surplus to requirements as is the original 4.4? small case diff (1990 320 AUTO) Travelled 75,000k. Also have auto Gearbox from same 75k car

Grant, thanks for the advice. This car is a 1990 320 Auto, import. It has been a one owner NZ since 30k. As the entire rear axle is out of the car i cleaned up the metal tag on the diff housing. The first 3 digits said 4.49 then had a couple of other numbers after. From this i assume the ratio is 4.49 ? or could this be a serial number? Thanks Mark

Just wondering if anyone can offer a some advice. I am currently preparing a 1990 320 for the BMW race series and have just noticed that the rear diff ratio is a 4.49. I assume this was because the car was an auto model. Which model can i obtain the 4.1 ratio as required for the race series. Also am i correct in thinking that the rear diff from the south African models a much heavier than the NZ 318/320? Many thanks